+ mm-damon-sysfs-do-not-ignore-callbacks-return-value-in-damon_sysfs_damon_call.patch added to mm-hotfixes-unstable branch

+ mm-damon-sysfs-do-not-ignore-callbacks-return-value-in-damon_sysfs_damon_call.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/damon/sysfs: do not ignore callback's return value in damon_sysfs_damon_call()
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-damon-sysfs-do-not-ignore-callbacks-return-value-in-damon_sysfs_damon_call.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-sysfs-do-not-ignore-callbacks-return-value-in-damon_sysfs_damon_call.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Akinobu Mita <akinobu.mita@gmail.com>
Subject: mm/damon/sysfs: do not ignore callback's return value in damon_sysfs_damon_call()
Date: Sat, 20 Sep 2025 22:25:46 +0900

The callback return value is ignored in damon_sysfs_damon_call(), which
means that it is not possible to detect invalid user input when writing
commands such as 'commit' to
/sys/kernel/mm/damon/admin/kdamonds/<K>/state.  Fix it.

Link: https://lkml.kernel.org/r/20250920132546.5822-1-akinobu.mita@gmail.com
Fixes: f64539dcdb87 ("mm/damon/sysfs: use damon_call() for update_schemes_stats")
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[6.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/sysfs.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/mm/damon/sysfs.c~mm-damon-sysfs-do-not-ignore-callbacks-return-value-in-damon_sysfs_damon_call
+++ a/mm/damon/sysfs.c
@@ -1592,12 +1592,14 @@ static int damon_sysfs_damon_call(int (*
 		struct damon_sysfs_kdamond *kdamond)
 {
 	struct damon_call_control call_control = {};
+	int err;
 
 	if (!kdamond->damon_ctx)
 		return -EINVAL;
 	call_control.fn = fn;
 	call_control.data = kdamond;
-	return damon_call(kdamond->damon_ctx, &call_control);
+	err = damon_call(kdamond->damon_ctx, &call_control);
+	return err ? err : call_control.return_code;
 }
 
 struct damon_sysfs_schemes_walk_data {
_

Patches currently in -mm which might be from akinobu.mita@gmail.com are

mm-damon-sysfs-do-not-ignore-callbacks-return-value-in-damon_sysfs_damon_call.patch